IDO2 and neoplasm: Moreover, a preclinical studydemonstrated that in mice treated with a combination of PEGPH20 and shIDO-ST, a Salmonella-based therapy which targets the immunosuppressive molecule indoleamine 2,3-dioxygenase (IDO), there was a significant reduction in tumor burden, an increased infiltration of immune cells into the desmoplastic stroma of pancreatic cancer, and an enhancement of FasL-mediated apoptosis of tumor cells [170].